The present invention relates to yarn winding apparatus of the type wherein a tubular yarn bobbin is supported for rotation between two rotatable clamping plates. Yarn winding apparatus of this general type are disclosed for example in German Patent DE 35 16 522, U.S. Pat. No. 4,126,279, and copending U.S. application Ser. No. 07/565,814.
In winding apparatus of the described type, the problem of reliably threading the yarn to the new winding bobbin, and effecting a clean cut of the yarn length between the waste removal system and the winding bobbin continues to exist, in particular where doffing is conducted automatically. In the winding apparatus as disclosed in the referenced U.S. patent, the yarn is first guided over the yarn bobbin so as to partially loop the same, and it is then placed over the edge of the clamping plate with an axial component directed outwardly from the winding zone. In such known apparatus, it may occur that undesired long yarn ends project from the yarn reserve, which have different lengths from package to package, or depending on the quality of the yarn, attempts to thread the yarn may turn out to be unsuccessful. These attempts end up with a yarn break, with yarn remnants being found on the bobbin, between the bobbin and the clamping plate, and in the groove of the clamping plate. Attempts have been made to avoid yarn remnants between the bobbin and the centering plate, in that the inner rim of the centering plate extends inwardly far beyond the adjacent edge of the bobbin. However, a large projecting length can lead, in the case of automatic doffing, for example, with the use of so-called doffers, to problems with the removal of the full packages.
Accordingly, it is the object of the present invention to provide a yarn winding apparatus and method, having an improved thread-up capability, and which avoids the problems with the doffing of packages, which exist in the prior apparatus.